Hello,Matt
Thanks again.
What you said("Use -ksp_type preonly -pc_type lu") means that I should use
a direct solver.And I am puzzled.
(1)I think this problem (single processor is ok and more than one are
problematic)is typical,but I cannot
find useful infomation both in the manual and the petsc-users.So can you give
me some explanation for this
phenomenon.
(2)When I use -pc_type lu,the error message is "Matrix format mpiaij does
not have a built-in PETSc LU!".
(3)The manual says that "This approach prevents the user from the
unexpected surprise of having a
corrupted matrix after a linear solve"(P72).So do you mean the problem of mine
is here?
(4)Generally I want to use the iterative approach other than the direct
method.
As a beginner,I have to learn more about the manual.And also I think an
experienced senior will be a more
useful help for me because I have gotten stuck on this problem for more than a
week.
Thanks. Jim
>At 2012-05-26 20:17:42,"Matthew Knepley" <knepley at gmail.com> wrote:
>Use -ksp_type preonly -pc_type lu.
> Matt
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